GDNUM
GDNUM allows the user to select grids by number in the following ways:
GDNUM = range
The first and last grid numbers in the range are separated
by a -. If an increment is included, it will be ignored.
GDNUM = list
The grid numbers in the list are separated using semicolons.
GDNUM = ALL
All the grids in the file will be included.
GDNUM = LIST
All the grids in the file will be listed. The user will
be prompted to select the grids to be included.